Hello @YWWP,

Since the payment term option is only available in invoices, you'll want to add a custom field to your estimate. Let me walk you through how.

1. Go to Gear, then Custom Form Styles.
2. Edit your estimate template.
3. Choose the Content tab, then select the header part of the estimate.
4. Scroll down and click the +Content field link.
5. Mark the box and enter "Payment Term".
6. Hit Done. Please see attached screenshots for steps 4 and 5 below.

After editing your template, you can manually add the term on your estimate and sent it to your customers. Please check this article and a short video clip for your reference.

• How to Adjust Invoice Payment Terms in QuickBooks Online.

• How to Set Up QuickBooks Payments.

I'd be around if you have questions. Feel free to swing by anytime. Thank you and have a wonderful day ahead.